Art of cracking hydrocarbons



E. C. HERTHEL El' AL ART oF CRACKING HYDRocARBoNs Feb. 26, 1935.

Filed Nov. 1, 1929 2 Sheets-Sheet 1 .Nm mum ATTORN EYS Feb. 26, 1935. E, Q HERTHEL Er AL 1,992,614

ART OF CRACKING HYDROCARBONS Filed Nov. 1, 1929 2 sheets-sheet 2 ,fz-5f. a. F575.

ATTORNEYS Patented Feb. 26, 1935 Thomas" De Colon ,-Tit, j

Maine Application Nvember 1, 1951591,A vserial-ivo. 403,985 3 Clim'sf (o1. 196248)* This invention` relates 'to 'iinprovment's'ir the? manufacture' of lower boiling hydrrbnoilsg' primarylvaporizing -zone producedlfrornvapor Such 'asgasoline and 'gasoline-'containing"distillf atmospheric pressure. Y 4

This .invention is, in one aspect, alurther pors'V of "ther cracked-oil atmospheric pressure craeked'foilarefsubjecte tion in which componentsff-ltheapr' higboiling than suitable as componentsofl thesevapors arev'subjected--toa cordensing'f'opi "i eration,- iniwhich howeveronly part'of the vapors may be condensed, irrwhich components higher boilingthan suitable as components 'of fthe de` siredproduet are condensedandl this condensate is also returned to the heating'zonef-and forcefrfwdense 91s 'suppiiedt tanki'othfghbrihe 40 therethrough;

According lto the present invention, the reux condensateY from the primary vaporizing" zone is passedfin the heatingzonein heat-exchange n i k n Y i i Wmme-heating'gases whiletheiatterhare'au15*to"condensenforipartial-Condgeff *16ff v derisatfrmcondens'er 16 is subpliedt'o -taLrilsfl'A 45 4highest temperature'and before they pass `ir heat exchange with thecondensate'f from the secondary vaporizing nzone; *and the "condensate" f 1 vapori'zing zone; :The 'reflux Acondensate-'frein jth `taken 'oiunder high pressure is "relatively fre#l the-heating zone, in heatgexchangewith the heating gases after the latter are 'ati a tempera"-1 ture-reducedby the first heatnexchajnge; and residualf'unvaporized f oil containing-:pitch con;l stituents` produced 'in the fcrackin'g' operation?. notwpermitted again'to pass :through the heati nection 23 by means of pump 25, and oil from tank 17 is supplied to connection 24 by means of pump 26.

Raw oil may be used as a condensing medium in the condensers 9 and 16. For example, raw oil may be passed successively through the con.

densers 9 and 16 in indirect heat exchanging relation with the vapors therein by means of pump y 27 and connections 28, 29 and 30 and then introduced either into tank 10 or tank 17 or both tanks 10 and 17 through connections 31 and 32. Raw oil may be supplied directly to tank 10 through connection 33 and to tank 17 through connection 34. Excess condensate mixture may also be discharged through connections 33 and 34. Pressure in drum 6 may be maintained and regulated by means of valve 35 or valve 36 or by means of suitable valves beyond the condenser 19.l Pressure in drum 1`4 may be regulated by means of valve 37 or valve 38 or by means of suitable valves beyond the condenser 20.

Drum 6 is advantageously externally unheated, being heated internally only by vthe heat of the hotoil products discharged through connection 7. /It may, however, be mildly heated externally by meansof furnace 40. It is with advantage lagged or thermally insulated to minimize heat loss. Drum 14 is advantageously externally unheated, and is with advantage lagged or thermally insulated to minimize heat loss. Connec- Vtions 12, l1 and' 23, and 18 and 24 and tanks 10 i and, 17 are also with advantage lagged or thermally insulated to minimize heat loss.

In the manufacture of gasoline, for example, thefurnace 39 may be operated so that the hot .oil products discharged from the heaters 21V and 22 are at Aa temperature as discharged through connection 7 in the general vrange of 800-1200 F.,the drum 6 may be maintained under a pressurein the neighborhood of 1D0-300 pounds per square inch andthe drum 14 may be maintained under a pressure in the neighborhood of 0-50' pounds per square inch. Raw oil, gas oil for example, may besupplied entirely to tank 17, or severalrraw oils may be supplied to the tanks 10 ,and17 according to the extent to which they are refractory to the cracking conditions maintained in theheaters 2 1 and 22, light gas oil for example maybe suppliedtotank 10 and heavy gas oil for example to tank .17; Vaporization in drum 14,may vbe carried only far enough to leave a fluxork heavy residue which can be removed as a liquid orit may be carried so far that only coke.

or acokey mass remains.

Instead of connecting the heaters 21 and 22 in zseriesw, as illustrated in Fig. l, each` of these heaters may be arranged to discharge directly into drum 6 through connection 7, as illustrated in Fig. 2, in which the same parts have thesame reference numeral as in Fig. 1 with the letter a appended. A condenser providing for direct heat exchange between the condensing medium and the vapors may be rsubstituted for the condenser 16 illustrated in Fig. 1. As illustrated in Fig. 3, in which the saine parts bear the same reference numeral as in Fig. 1 with the letter b appended, raw oil, gas

oil for example, may be introduced directly into condenser 16D through connection`41 and supplied to the tank 17 in admixture with the condensate from this condenser through-connection 18h.'

" l The single reux condenser 9 illustrated in Fig.

1 may be replaced by a pair of reflux condensers 9c and 9c, as illustrated in Fig. 4, in which the same parts bear the same reference numeral as in Fig. l with the letter c appended, reilux condensate from the first 9'c being returned directly to drum 6c through connection 42 and reflux condensate from the second 9c being supplied to the heater overwhich the heating gases first pass through connection 11c. It will be apparent that connection 42 must include a pump if a higher pressure is maintained in the drum 6c than inthe condenser 9c.

The single rellux condenser 9 illustrated in Fig. 1 may be replaced by a pair of reflux condensers 9d and 9d, in which the same parts bear the same reference numeral as in Fig. 1 with the letter d appended, reflux condensate from both the condensers 9d and 9d being supplied to the heater over lwhich the heating gases rst pass through connection 11d, raw oil eventually supplied to one of the heaters beingused as a condensing medium in the condenser! 9d, and an Y easily cracked raw oil being used as a'condensing medium in the condenser 9'd and then introduced directly into the drum 6d through connection 43 by means of pump A44. vReilux'condensers duced directly into -the'drum 6d through connection 43 and raw oil eventually supplied to one of the heaters may be used as a condensing medium in the condenser through which the vapors next pass; and with this arrangement both reux condensers maybe of the general type (illustrated. in Fig. 3) providing for direct'heat exchange between the condensingmedium and the vapors, -the condensate from the first reux `condenser then being-returned directlyto drum 6d (as inthe apparatus illustrated in Fig. 4) in admixture with the raw` oil condensing medium introducedinto this We claim: 1. In cracking hydrocarbon oils, the improve-'- ment .which comprises forcing high vvboiling oil reflux condenser.

vthrough a heating zone and heating itto a cracking temperature therein byheat exchange with heating gases and discharging the hot oil products from the heating zone into a primary vaporizing zone, takingv olf Avapors from this primaryvaporizing `zone under superatmospheric pressure and subjecting them to reflux condensation, discharging unvaporized oil from the primary vaporizing zone into a secondary vaporizing zone maintained under a pressure lowerthan .thatprevailing in the primary. vaporizing zone, taking 01T vapors from this secondary vaporizing zone and subjecting them tocondensation, and, in the heating zone, passing condensate from said reflux condensation in heat exchange with the heating gases before the latter pass in heat exchange with condensatefrom said Acondensation'and passing condensate from said condensation in heat exchange with the heating gases after the latter have been tempered by the first heat exchange Without permitting any unvaporized oil containing pitch constituents produced in the cracking operation again to pass through thel heating zone from either of the vaporizing zones. l

2. In cracknghydrocarbon oils, the improvement which comprises forcing high boiling voil through a heating zone and heating it to a crackingtemperature therein by heat. exchange with heating gases and discharging the hot oil products from the heating zone into a primary vaporizing zone, taking off vapors from this primary Vaporizing zone under superatmospheric pressure and subjecting them to reflux condensation, discharging unvaporized oil from the primary Vaporizing zone into a secondary vaporizing zone maintained under a pressure lower than that prevailing in the primary vaporizing Zone, taking off vapors from this secondary Vaporizing zone and subjecting them to condensation, and, in the heating zone, passing condensate from said reux condensation in heat exchange with the heating gases before the latter pass in heat exchange with condensate from said condensation and passing condensate from said condensation in heat exchange with the heating gases after the latter have been tempered by the irst heat exchange without permitting any unvaporized oil containing pitch constituents produced in the cracking operation again to pass through the heating zone from either of the Vaporizing zones, and supplying relatively less refractory raw oil to the heating zone with the condensate from said condensation and supplying relatively more refractory raw oil to the heating zone with the condensate from said reiiux condensation.

3. In cracking hydrocarbon oils, the improvement which comprises forcing high boiling oil through a heating zone and heating it to a cracking temperature therein by heat exchange with heating gases and discharging the hot oil products from the heating zone into a primary Vaporizing zone, taking oi vapors from this primary vaporizing Zone under superatmospheric pressure and subjecting them to reiiux condensation, discharging unvaporized oil from the primary vaporizing zone into a secondary vaporizing zone maintained under a lower pressure than that prevail- 1'0 ing in the primary Vaporizing Zone, taking off vapors from this secondary vaporizing zone and subjecting them to condensatiomand, in the heating zone, passing condensate from said gases before the latter pass in heat exchange with condensate from said condensation and passing condensate from said condensation in admixture with the thus hea-ted condensate from said reiiux condensation in heat exchange with the heating 20 through the heating zone from either oi the va- 25 porizing Zones.

EUGENE C. HERTHEL. THOMAS DE COLON TAIFFT.

reiiux condensation in heatexchange with the heating 15 

